The field of the invention is tools and the present invention is particularly concerned with wrenches having a sliding side jaw.
The state of the art of adjustable wrenches may be ascertained by reference to U.S. Pat. Nos. 3,640,159; 3,673,896; 3,901,107; 4,028,970; and 4,375,174, the disclosures of which are incorporated herein by reference.
U.S. Pat. Nos. 3,901,107 and 4,028,970, are the most pertinent references to the present invention because they show adjustable jaw open end wrenches having thumb operated pulleys and driving belts for adjusting the jaws.
Conditions arise in the use of the prior art adjustable wrenches wherein it is impossible or cumbersome to manually adjust the sliding jaw. This can happen when it is necessary to remove the wrench from the work for adjustment. Also, it is diffiucult to adjust the prior art wrenches when the fingers are restricted by gloves or impaired by joint disease.